Some back up systems operate by having the network administrator identify a time of day during which little or no network activity occurs. During this time, a network administrator can allow a backup system and the data files stored on the computer network to be backed-up, file by file, to a long term storage medium, such as a tape backup system. Typically the network administrator will back up once a week, or even once a day, to ensure that the back up files are current. Such a backup process can be a time consuming, labor intensive, and cumbersome. As computer networks generally operate twenty-four hours a day, seven days week, it can be difficult for a system/network administrator to identify a time period during which network resources may be relegated to a back up procedure. Further, increased users and numbers of changes on a regular daily basis diminishes the value of a back up system that operates once a week or once a day. Systems that only generate back up data periodically are thus of a reduced value.
In some alternate systems, a data server and a backup server can maintain mirrored data files and backup files. For example, in one such system, a data server can execute change requests on data files and transmit the change requests to the backup server, and the backup server can execute the change requests on the corresponding backup files to keep the backup files mirrored to the data files. Such systems may be viewed as lacking efficiency in their use of data processing capacity and data storage capacity, as two copies of all files are generally required.